This invention relates generally to an installation for evacuating emanations in the taphole region of shaft furnaces, particularly blast furnaces. More particularly, this invention relates to an installation for evacuating emanations in the taphole region of a shaft furnace of the type which has a blast connection arrangement around the furnace bosh, together with a blast connection stage or platform for the inspection and servicing of the blast connections; and in which the molten pig iron is periodically tapped with the aid of tapping means and run off through a main tapping runner or spout.
In accordance with the present invention, the expressions "emanations" is used broadly as a collective term for the accumulation of smoke, gases, vapors and dust particles occurring mainly upon the discharge of pig iron in the region of the taphole and tapping spout of a blast furnace. These emanations are not only dangerous to the health of operators, but generally pollute the environment. In addition, the emanations soil and corrode the operating plant, both within and beyond the region of the taphole and tapping spout.
In order to keep the deleterious effects of such emanations within more or less tolerable limits and in accordance with the prior art, blast furnace installations have been provided (particularly in the case of larger installations where problems of space are not so important) with stationary exhaust hoods or scoops and the like, as well as exhaust ducts, which laterally draw off the emanations accumulating above the tapping runner.
The above-discussed measures employed in the prior art have a number of disadvantages and shortcomings. For example, the stationary exhaust scoop cannot be taken as far down towards the taphole region as would be desired (in order, for example, to avoid hindering the operation of the taphole drilling machine and the taphole gun). Not only is the stationary exhaust scoop limited solely for larger furnaces because of the large space required, but in addition, its effect is very unreliable because of its relatively great distance from the critical region (e.g. where emanations originate). Moreover, if the action of the exhaust scoop is to be satisfactory to any extent, higher air throughputs must be obtained, with corresponding high power consumption leading to high costs.
The aforementioned exhaust ducts for the emanations occurring above the tapping spout itself must be laterally positioned in order not to hinder the operation of the drilling machine and taphole gun as mentioned above. This process of exhausting the emanations is consequently not effected in the direction of the natural thermal upthrust of the hot emanations, so that a relatively great suction power is required to draw off the emanations laterally; instead of vertically upwards. This suction power is further considerably increased by the fact that a large part of the suction flow passing through is made up of unpolluted air from the region above the tapping spout, unless the latter is covered in the exhaust region (which in turn would entail other disadvantages). A further disadvantage of lateral exhausting consists of the deposits which, in the course of time, build up or may build up on the hard to reach bottom of the horizontal exhaust ducts.